Method of Bleaching Teeth

ABSTRACT

A method for bleaching teeth comprising applying a first bleaching composition having a first concentration of a bleaching agent to teeth to be bleached immediately followed by applying a second bleaching composition having a second concentration of a bleaching agent to teeth to be bleached. The second concentration of the bleaching agent is less than the first concentration of the bleaching agent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/449,186, filed Aug. 1, 2014, the entirety of which is incorporatedherein by reference.

FIELD

The present method relates to the field of dental whitening and inparticular to methods of use of dental bleaching compositions.

BACKGROUND

Stained or discolored teeth are considered as a cosmetic impairment.Teeth's whitening is a cosmetic treatment done to improve the appearanceof teeth. Teeth are whitened to remove impairments such as thoseresulting from the effects of coffee, cigarettes, and other substancesthat permanently stain or discolor teeth. Different techniques of teethwhitening or bleaching are known and relatively simple proceduresimproving the stained teeth appearance exist. The procedures can beconducted in a dental clinic, office or in a residential environment.

A variety of dental bleaching compositions and dental bleaching devicesor trays exist on the market. Such dental bleaching compositions aretypically applied to a person's teeth using a dental tray configured soas to retain the dental composition against the person's teeth.Treatment time can vary between about 10 minutes to a few hours andalthough conducted in a residential environment it can temporarily limitthe user's freedom of speech, movement and function during the treatmentperiod. In addition, it is uncomfortable for the user to keep a dentaltray in the mouth over relatively long periods of time. User comfortduring the teeth bleaching treatment duration may be improved byshortening the time of bleaching.

Most common bleaching agents used are peroxides, including but notlimited to hydrogen peroxide, carbamide peroxide, sodium perborate, andsodium percarbonate. The simplest way to shorten the treatment time canbe to increase the concentration of the peroxide. However, use of higherconcentrations of bleaching agents (e.g., peroxides) can result inirritation and even some damage of oral mucosa such as gums or lips orother soft tissue.

As a result, the current methods of application of bleaching agentsdisclose using lower concentrations of bleaching agents, applyingprotection to the gums such as a protective light curable gingivalprotector or similar prior to application of the bleaching agent orusing bleaching agents other than hydrogen peroxide such as chlorinedioxide and oxy-chlorine anions (U.S. Pat. No. 8,377,423),

Another way to accelerate bleaching time and speed up the chemicalreaction related to the bleaching process can be concurrent applicationof heat or light or DC (Direct Current) electric current to thebleaching composition as disclosed in U.S. Pat. No. 7,775,795.

SUMMARY

Presented is a method of safe application of a dental bleaching agent,mainly hydrogen peroxide to teeth to speed up and shorten a teethwhitening treatment session while maintaining the safety of thetreatment. The method can include applying initially a first dentalwhitening composition having a high concentration of a bleaching agent(e.g., hydrogen peroxide) to the teeth followed by applying a seconddental whitening composition having a low concentration of a bleachingagent.

The method can also include generating DC electrical current through themixture of the applied dental whitening compositions so that toaccelerate the activity of the bleaching agent and further shorten theteeth whitening treatment time.

The first dental whitening composition having a high concentration ofthe bleaching agent and the second dental whitening composition having alow concentration of a bleaching agent can be applied consecutivelyand/or concurrently during the same teeth whitening treatment session.

The method also includes applying the first dental whitening compositionhaving a high concentration of the bleaching agent and the second dentalwhitening composition having a low concentration of a bleaching agenttogether and allowing sufficient time so that the bleaching agentconcentration within the mixture of the compositions stabilizes bydiffusion at a concentration sufficiently high to whiten the teeth butnot cause any irritation to the oral mucosa.

The first composition is operative to penetrate deep within the enamelwherein the high concentration of the hydrogen peroxide in the firstcomposition operates to erase most of embedded stains. Applying thesecond composition to the same stains for a same period of time wouldnot affect the embedded stains affected by the first composition. Hence,the first composition penetrates deep within the enamel to erase most ofembedded stains not affectable by the second composition when appliedfor a same period of time.

The bleaching agent (e.g., hydrogen peroxide) can be an ingredient in,for example, a whitening gel being, for example, a composition of one ormore ingredients including hydrogen peroxide as a bleaching agent, across-linked polyacrylate polymer as a thickening component, and theelectrical conductivity enhancing ingredients such as electrolytes.Potassium nitrate and/or potassium hydroxide are examples of suchelectrolytes. Each of them could be included alone in the composition ora mix of both of them could be used to enhance conductivity of thedental bleaching gel composition.

Other ingredients can include Glycerin, propylene glycol and water areused as vehicles and solvents in which other ingredients or componentsare mixed to prepare the dental bleaching gel composition.

Other ingredients affecting antimicrobial and oxidizing properties ofthe gel, mouth refreshing components and components improving bleachinggel viscosity and wetting properties are added as required to thecomposition.

The concentration of bleaching agent in the composition can vary (i.e.,lower) over time so that to drop below a concentration level that canirritate the oral mucosa,

Applying the dental whitening composition or gel could be done byplacing the composition or gel in a dental cosmetic treatment tray orapplicator configured to retain the dental composition against theperson's dental arcade, such as the Pearl®. applicator commerciallyavailable from Illuminage Beauty LTD, Yokneam Industrial Zone, 2069201ISRAEL).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frontal view simplified illustration of an example of afirst step of a safe method for cosmetic whitening of teeth;

FIG. 2 a frontal view simplified illustration of a second step of anexample of a safe method for cosmetic whitening of teeth; and

FIG. 3 a frontal view simplified illustration of yet another step of anexample of a safe method for cosmetic whitening of teeth.

DESCRIPTION

In the context of the present disclosure the terms “dental bleaching”and “dental whitening” have the same meaning.

DC electric current is known to accelerate the bleaching reaction. TheDC electric current activates the bleaching agent and accelerates thebleaching reaction. The DC current activates certain ingredients of aspecially formulated whitening gel, allowing it to penetrate deep withinthe enamel to erase most of embedded stains without sensitivity orirritation. Use of DC electrical current and specially formulated gelhas proved to deliver whitening results much better than light or heatactivated teeth whitening treatments.

The term “dental whitening composition having a high concentration ofhydrogen peroxide” and “the first composition” mean the same and referto a dental whitening bleaching agent composition having a concentrationof hydrogen peroxide between 20% and 50% (w/v).

The term “dental whitening composition having a low concentration ofhydrogen peroxide” and “the second composition” mean the same and referto a dental whitening bleaching agent composition having a concentrationof hydrogen peroxide between 0.1%-15% (w/v).

As described above, applying bleaching agents such as hydrogen peroxideto teeth could be harmful to the oral mucosa and other adjacent softtissue. However the effect of a bleaching agent such as hydrogenperoxide on tissue depends not only on the concentration of thebleaching agent in the applied bleaching composition but also on thelength of contact time (i.e., direct contact) of the bleaching agentwith the tissue.

Application of higher concentrations of hydrogen peroxide, e.g.,concentrations between 20% and 50% (w/v) can be highly effectivewhitening or bleaching teeth however, contact time must be short inorder to avoid irritation to oral mucosa and other soft tissue.

On the other hand, a low concentration of hydrogen peroxide, e.g.,concentrations of 0.1%-15% (w/v) can be safer to oral mucosa and otheradjacent soft tissue but can require and extended contact time to beeffective and whiten teeth satisfactorily. Another aspect of treatmentwith hydrogen peroxide is that the longer the contact time of hydrogenperoxide, even at lower concentrations, the higher the risk ofafflicting irritation to the oral mucosa and adjacent soft tissue.

The below described method combines a first dental whitening compositionhaving a high concentration (20% and 50% (w/v)) and a second dentalwhitening composition having a low concentration (0.1%-15% (w/v)) of ableaching agent applied for a longer duration and allowing sufficientapplication time of the mixture so that over time the bleaching agentconcentration within the mixture of the compositions in contact with theteeth and oral mucosa stabilizes by diffusion at a concentrationsufficiently high to whiten the teeth but not cause any irritation tothe oral mucosa and adjacent soft tissue. In other words, theconcentration of the bleaching agent in the whitening composition incontact with the teeth and oral mucosa is different and can vary (i.e.,become lower) over time by diffusion so that to drop below aconcentration that can irritate the oral mucosa.

The first dental whitening composition is operative to penetrate deepwithin the enamel wherein the high concentration of the hydrogenperoxide in the first dental whitening composition operates to erasemost of embedded stains. Applying the second dental whiteningcomposition to the same stains for a same period of time would notaffect the embedded stains affected by the first dental whiteningcomposition. Hence, the first composition penetrates deep within theenamel to erase most of embedded stains not affectable by the secondcomposition when applied for a same period of time.

Applying the first dental whitening composition or gel could be done bymeans of an applicator or brush 102 (FIG. 1). Applying the second dentalwhitening composition or gel to the teeth can be done by placing thesecond dental whitening composition in a cosmetic treatment tray orapplicator 202 (FIG. 2) configured so as to retain the dentalcomposition against the person's dental arcade 100 (FIG. 1). The tray orapplicator could be such as the Pearl® applicator commercially availablefrom Iluminage Beauty LTD, Yokneam Industrial Zone, ISRAEL and depictedin FIG. 2 by phantom lines.

The method includes applying a thin film of a first composition (FIG. 1)having a high concentration of a bleaching agent for a very shortduration immediately followed by applying a second composition (FIG. 2)including a low, safe concentration of a bleaching agent withoutirritation of the oral mucosa and other adjacent soft tissue andallowing sufficient time so that the bleaching agent concentrationwithin the mixture of the compositions stabilizes by diffusion at aconcentration sufficiently high to whiten the teeth but not cause anyirritation to the oral mucosa.

Additionally and optionally, the bleaching gel could also include one ormore electrical conductivity enhancing ingredients such as electrolytes.When using a bleaching gel including electrical conductivity enhancingingredients, the method of application could include applying a thinfilm of a first dental bleaching gel (FIG. 1) producing a highconcentration of hydrogen peroxide (i.e., 20% and 50%) immediatelyfollowed by applying to the treated teeth an applicator 202 (FIG. 2)including a second dental bleaching gel (not shown) producing a lowconcentration of hydrogen peroxide (i.e., 0.1% and 15%) and activatingapplicator 202 by pressing on an ON/OFF button 304 (FIG. 3) and applyinga DC current through the mixture of compositions retained in theapplicator and in contact with the teeth so that to accelerate thebleaching activity of the hydrogen peroxide on teeth and shorten theteeth bleaching treatment time.

The first dental whitening composition having a high concentration ofthe bleaching agent and the second dental whitening composition having alow concentration of a bleaching agent can be applied consecutivelyand/or concurrently during the same teeth whitening treatment session.

The bleaching agent can be an ingredient in, for example, a whiteninggel being, for example, a composition of one or more ingredientsincluding hydrogen peroxide as a bleaching agent, a cross-linkedpolyacrylate polymer as a thickening component, and the electricalconductivity enhancing ingredients such as electrolytes. Potassiumnitrate and/or potassium hydroxide are examples of such electrolytes.Each of them could be included alone in the composition or a mix of bothof them could be used to enhance conductivity of the dental bleachinggel composition.

Other ingredients can include Glycerin, propylene glycol and water areused as vehicles and solvents in which other ingredients or componentsare mixed to prepare the dental bleaching gel composition.

Other ingredients affecting antimicrobial and oxidizing properties ofthe gel, mouth refreshing components and components improving bleachinggel viscosity and wetting properties are added as required to thecomposition.

It will be appreciated by persons skilled in the art that the presentmethods are not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the methods includes bothcombinations and sub-combinations of various features describedhereinabove as well as modifications and variations thereof which wouldoccur to a person skilled in the art upon reading the foregoingdescription and which are not in the prior art.

What is claimed is:
 1. A method for bleaching teeth comprising: applyinga first bleaching composition having a first concentration of a firstbleaching agent to teeth; placing a second bleaching composition havinga second concentration of a second bleaching agent in a dental tray; andsubsequently applying the dental tray to the teeth; wherein the secondconcentration of the second bleaching agent is less than the firstconcentration of the first bleaching agent.
 2. The method according toclaim 1 wherein the first bleaching agent in the first bleachingcomposition is hydrogen peroxide at a concentration between 20% and 50%(w/v).
 3. The method according to claim I wherein the second bleachingagent in the second bleaching composition is hydrogen peroxide at aconcentration of between 0.1% and 15% (w/v).
 4. The method according toclaim 1 wherein the second bleaching composition is applied immediatelyfollowing the application of the first bleaching composition.
 5. Themethod according to claim 1 wherein the first and second bleachingagents are the same.
 6. The method according to claim 5 wherein thefirst and second bleaching agents are one of hydrogen peroxide,carbamide peroxide, sodium perforate, and sodium percarbonate.
 7. Themethod according to claim 6 herein the first and second bleaching agentsare hydrogen peroxide.
 8. The method according to claim 1 furthercomprising, after applying the second bleaching composition, applying aDC current through the first and second bleaching compositions, thefirst and second bleaching compositions retained in the dental tray andin contact with the teeth.
 9. The method according to claim I whereinthe first bleaching agent in the first bleaching composition has aconcentration between 20% and 50% (w/v) and the second bleaching agentin the second bleaching composition has a concentration between 0.1% and15% (w/v).
 10. The method according to claim 1 wherein the firstbleaching composition and the second bleaching composition are appliedduring the same teeth whitening session.
 11. A method for bleachingteeth comprising: applying a first bleaching composition having a firstconcentration of a first bleaching agent to teeth; subsequently applyinga second bleaching composition having a second concentration of a secondbleaching agent to the first bleaching composition on the teeth, thesecond bleaching composition being a gel; wherein the secondconcentration of the second bleaching agent is less than the firstconcentration of the first bleaching agent.
 12. The method according toclaim 11 wherein the first bleaching agent in the first bleachingcomposition is hydrogen peroxide at a concentration between 0% and 50%(w/v).
 13. The method according to claim 1.2 wherein the secondbleaching agent in the second bleaching composition is hydrogen peroxideat a concentration of between 0.1% and 15% (w/v).
 14. The methodaccording to claim 11 further comprising applying a DC current throughthe first and second bleaching compositions, the first and secondbleaching compositions retained in an applicator and in contact with theteeth.
 15. A method for bleaching teeth comprising: applying a firstbleaching composition having a first concentration of a first bleachingagent to teeth; subsequently applying a second bleaching compositionhaving a second concentration of a second bleaching agent to the teeth;and applying a DC current through the first and second bleachingcompositions which both remain on the teeth; wherein the secondconcentration of the second bleaching agent is less than the firstconcentration of the first bleaching agent.
 16. The method according toclaim 15 wherein the first bleaching agent in the first bleachingcomposition is hydrogen peroxide at a concentration between 20% and 50%(w/v).
 17. The method according to claim 15 wherein the second bleachingagent in the second bleaching composition is hydrogen peroxide at aconcentration of between 0.1% and 15% (w/v)
 18. The method according toclaim 15 wherein the first and second bleaching compositions are thesame.
 19. The method according to claim 15 wherein the first and secondbleaching agents are hydrogen peroxide.